1. Field of the Invention
The present invention relates to a control device for a rotary printing machine and, more particularly, to a device for quickly establishing a production-run state in a printing group of a rotary printing machine.
2. Description of the Related Art
In web-fed and sheet-fed rotary printing machines, print quality is generally unsatisfactory during initial start-up (either at the start of production or after an interruption in printing). The printed products are typically not printed with the requisite print quality until the printing group achieves a so-called production-run state. Consequently, the quality of the products printed during the initial start-up period of the printing machine will generally be unacceptable. By manually adjusting the setting of the inking unit and, as applicable, the wetting unit, print operators attempt to reduce the amount of broke. Success here depends on experience and on the timely intervention by the operatorxe2x80x94both being subjective and susceptible to variation. Furthermore, different interruptions in printing require different adjustment measures. For example, a brief interruption may only cause the inking profile to drift and therefore require only an adjustment to the inking unit. For longer interruptions such as, for example, a plate change, the ink profile set over the breadth of the inking unit can be lost due to lateral spread when the inking unit is positioned away from the printing form, as required to change the plate. After the plate change, there may be a special need for ink and, in some cases, a dampening agent requiring adjustment to the inking and dampening units. Still other conditions prevail after a printing blanket is washed. Furthermore, register marks that are not printed initially may lead to spoilage as the result of the subsequent adjustment of the register.
European Patent Number EP 0 403 861 B1 proposes a process for producing a profile for offset printing machines that approaches production-run printing. According to the proposed process, a control device serves to place the application rollers of the inking and dampening units onto the printing form, permanently or temporarily, during the inlet of ink prior to printing or during an interruption in printing. The control device also reduces the quantity of dampening agent supplied. As a result, the subject matter on the printing plate has a supportive effect on ink distribution. In addition, according to one embodiment, an ink control device can adjust the ink dispensing device. The control device itself is not disclosed in this reference.
It is accordingly an object of the present invention to provide a device that quickly establishes a production-run state in a printing group of a rotary printing machine after the printing cycle has been interrupted.
The instant invention provides a plurality of freely programmable memory devices having various different printing control programs stored therein. A plurality of switches manually or automatically connect the memory devices to a control computer. Following a printing cycle interruption, the operator or a machine control unit determine which of the control programs are necessary to return the printing machine to a production-run state based on the nature of the interruption, i.e. brief machine shutdown, plate change, printing-blanket washing, etc. A switch is then manually or automatically depressed to connect one of the memory devices to the control computer which then-controls the inking unit and, as applicable, the dampening unit in such way that an inking profile suitable-for production-run printing is quickly established. In this way, the amount of spoilage is minimized.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims.